Apparatus for detecting perforations in ammunition flash tubes



l 'atented Nov. 16", i948 APPARATUS FOR DETECTING PERFORA- TIONS IN AlHMUNITION FLASH TUBES Leo Meister, Irvington, Va. Application October 30; 1944, Serial No. 551,144

(Cl. 209111) (Granted under the act of March 3, 1883, as

8 Claims.

amended April 30, 1928; 370 O. G. 757) The invention, described herein may be manufactured and used by or for the Government for governmental purposes without the payment to me of any royalty thereon.

This invention relates to inspection devices, and is a continuation-in-part of my co-pending application Ser. No. 451,679, filed July 20, 1942, for Testing apparatus, now Patent No. 2,385,367, dated September 25, 1945.

A purpose of the invention is to provide a simple, quick and efiective method of inspecting primers for artillery ammunition and thelike to determine that no undesired openings or pinholes exist therein.

Another purpose is to provide a method of automatically selecting defective primers and segregating them from acceptable primers.

A further purpose is to provide an automatic method of ejecting defective'primers from the inspection device. 7

An additional purpose is to avoid the limitations of the use of a visual method of discovering defective primers.

Other purposes will become apparent from the description set forth herein.

In the manufacture and loading of ammunition primers for artillery shells, it is customary to insert a liner of paper or the like into the flash tube and to coat the exterior of the flash tube with a sealing compound like pitch, to keep out moisture which might render the primer inoperative if itgained access tents of the flash tube} Thus it is necessary to inspect the flash tube after the paper liner has been inserted and the outer pitch covering applied, and before filling it with black powder. The inspection should disclose any openings or pinholesin the pitch tube covering. The visual method of inspection does not yield good results because tiny pin holes are not easily seen. "Ihe'present invention proposes to improve the inspection procedure by means of a device by which light passing through a pinhole in the flash tube covering automatically causesthe defective tube to be ejected from the machine and dumped into a separate container for rejects.

Reference is now had to'the drawings in which; Figure 1 is a diagrammatic and schematic partly' cut-away view of the working parts of the tothe black powder con whole device, showing the primer flash tube in the machine in position for inspection,

Figure 2 is an elevational cut-away view of a flash tube with paper liner and pitch covering,

the tube surmounting a plastic inspection post,

Figure 3 is a sectional view taken on the line 3-3 of Fig. 2,

Figure 4 is a side sectional tion valve 60, and

Figure 5 is avi'ewtaken along line 5-5 of Fig. 4.

In Figure l, a coated and lined primer flash tube l which is to be inspected for pinholes, is placed over a plastic hollow inspection post 2 which has a photoelectric cell 3 over its lower end 4. The output wires 5 and 6 of the photoelectric cell 3 are connected directly across the coil of a sensitive relay 8 having an armature 9 carrying a movable contact I0 adapted to engage a fixed contact I I whereby an external circuit may be closed. The relay 8 has a permanent magnet I4 between the poles of which the pivoted movable coil 1 tends to rotate in a clockwise direction as the current generated by the photoelectric'cell 3 passes through the coil. Thearmature 9 mounted on coil 1, and carrying contact ID on its outer end, rotates with coil 1 and thus engages staview ofthe regulationary contact H. A number of one hundred watt incandescent lamps l2, are disposed around the test post 2 and connectedto a current source.

whereby they are kept lighted during testing and their light is cast on the outside of the flash tube 1 being inspected. Four or more of the lamps l2 should be used for good illumination. A dispersion cylinder l3 of frosted glass or the like is mounted between the lamps l2 and the test post 2 to scatter the light as it impingeson the exterior of the flash tube I. in the flash tube l,the light from the four lamps 12 passes through the pinholes and into the test post 2, through its polished side surfaces 51 being transmitted longitudinally within the test converts the light into electric current suflicient to actuate the'coil- 1 of the relay 8 moving the If any pinholes exist armature 9 and carrying the contact In against the contact I l.

The test post 2 has a longitudinal bore 58 open at the end 20 and connected at its other open end with a hollow tube 2| which connects to a compressed air tank 22. A valve 23 in the tube 2' is actuated by a solenoid 24 having a plunger 25 and adapted to open the valve 23 when current passes thorugh the solenoid 24, thus permitting compressed air to pass from the tank 22 through the tube 2| and through the bore 58 in the test post's}, Current is admitted to the solenoid 24 from the power source 26 by the relay 8 bringing the two contacts l0 and II together. It is thus apparent that when the valve 23 is open, permitting the compressed aihto, through it, the efiect of the air blast is tgblow theiflagh. tube l off the end of the test post 2. Thus a defective flash tube permits light to passthrough it, releasing the compressed air and ejeoting the defective tube.

An adjustable regulator valve 60 is inserted-in the tube line 2| for controlling the strength of.

the air blast by reducing the sizl e of the passage1.

Way for the air passing through the tube 2!. As h whi jfigure Lan 5. theya Ve 6. h s a base 6| attached sunpcrttfi; by means. or, screws. 63- A. plug; 6 rtl Q- a1.i ehap i rotatably fittedg into orres ondin hu h-con ca criej aihtheh se- 61- 1 .15.64 ha acy harit l. exten ion 5.6 .with a. .61: threaded tot outer end of the extension. A steel springwasher, 8...:aha ted. ov r the extensio ttse vestcm intain the conical plug 64 under longitudinalten ihhl ahtly. ithinthe. con cal h re. 6 The. c shaped member 59 is held against the base 6!. of the P essure. exerted ga nst. by th snrin. -waeh rtt.. Atransverse threw inthebe et! and .aeerre hhheine .bore I inthe; onical lug fitta ighed t erew this cchheeteda both. I

h h ta r-line'li e asto rz ov ile.at eagle ahcwh-.. Since. the. nu .61 ho ds.- thet prmgwasher Et -un e pres ure. t e

efiect' i h. drawitiahtlh together the assemb y. ompris ng. the. member. 5 t e. membe 4 nut .6 ari rwash'r; 6.5.50. th t rct t cahf me er. .9. causes, the. entire. sa d. aasemhlx. to rot te. as; a un t Eva uating-member: 6. 1 he sizeof t e air. passageway he adiuet a it has. been .io nd.

h .ria rhl at pressur t 3. pouudsper square. in .ihthejtestrost suitable or owing of a fla tube ahaut ur. i ches. n th. W ere he. 11 ub -51 longer a d n e heavier. h. 11. 4 blast. press re Wouldhenecessara. he. 91. .flash tube. wi lhecess tatetheuse .o acor= est. .nciihgl ionge testpa t...

A. deflector. plates. Zl. is. vot llr m Ul1 1$d-,,OI1. piv t 2li Q. atas.th edefective. flash t be I i ieeted y e a r blast, it is. in o .areieets ho per .9.-

If he. flash tubes not automatically hrown. into the iei ctsh nper a heait has. passe th estahcl.istche hte t uto ho per .0. Itmay be removed .fr m. est-nest Lhy hand. and. plac d w th t e aece tahleflaeh. ubes inhopper. 30... Or. t. may he. remo ed; nd. saplaeed mechanically. his hrhhse. he-tane zlimust bero e hro gh the hel t tcthen siti h 2.50 that. ahair blastthroughtest heat 2.-.wil1..bl .w. it ght nto -thee e per; A. aeo eh id. t ha t-a plun er aiattachedtovane Heat-a y su ta le po nt 35;.. th tp unge a ing h h hand eing: a tua ed hr. cur-t nt: pass ethrouehteoil. atawhe by; h

nluhgery ilt a drawn. in oj h i center. of; coil 4 thereby rotating vane 21 to position 32 and eitposing hopper 30 for acceptable flash tubes.

A foot treadle 31, having a pivot 38 at one end and a return spring 39 carries moving contacts 40, 4| and 42 adapted to engage stationary contacts 43, 44 and 45 respectively. When the pedal 31 is depressed by the operator for an acceptable flash tube, the contact engages contact 43 closing the circuit to the valve solenoid 24 and actuating it, causing an air blast through the test post 2 thereby ejecting the acceptable flash tube 1. At the same time the pressure of the operator on the foot pedal 3T has caused contacts 4! and 42 to engage contacts 44 and 45 respectively so that current is fed to the two leads 46 and 41 to the solenoid; coil 36-, causing the plunger 34 to be drawn;into the solenoid coil 36 and pulling with it the vane 21 rotating it to the position 32. Thus thehopper 30 is exposed and the acceptable flash tuhe-iszeiected; nto i by t air l st.

The light bulbs l2 may be replaced by other convenient sources of high illumination if desired. For example, acojlof fiuorescent light tubing may beplaced around-the test post 2 for this purpose, or mercury vapor lights may be used. By using a older lishtsou ea. it ayhepleceucloser to-the ob ct bein t st d. t out hav n ny. excess.

heat. pres nt. o. aftect the pitch covering. of. the. flash tubes being tested' ortheplastic test,post'2..

The pho oee1 .may. al o bem re sensitiv tothe old lighto the merc y vapor li h wi h con s endin advantaaesringr ater abilitytodetect.

very small pinholes...

It willbe seen from Figurefl thattheflashtube l is an elon ated cylindricaltubc. closed. atone end by. being. spun or by a cap r other. suitable method; and. is. prcv dedwith apluralityof spaced; o es I n the.s,ides,..or,th'e tube throu h. which. the flash of the black powder contents. comes outA pletely seal Qfi. any. pinholes that might. admit. moisture to the black powder whichis to be in rted in o the flash tube later.

A shown inEigure, 2., .the test post. 2-- onsists-1 of a cylinder of acrylic plastic having. acentral.

bore 58101:. passage ,Qf; th6z air. last It al a both ends 20 and 51 of the plastic coatedlwith a.

black paint to reflectthel'ight from (the ends back nto the. pla t c.

ward so that atitsnarrowestit has a diameter ua o. the ut ide iame er of thecylindrical. b f heE eSt .1 Q 2 andat its widest its'dit amet r s..-equal tothatprttheiightesensitive face. of. the, photoekctriccell It is; noted thatthea photoelectrio-cellfi musthave-azbore 53 through. 5 i s enterzso as tcmake itannular-inehape.for a1.-

1owine the lowernd or; the .t st p t t pass throu h it. Aecoating jl z of op que blacktpa nt; is. 2 applied overheslopingsides 5.4,; amall pa i of he ertical ides,..andhoth-endsof theaplasticz OE-and. ..s.o as to ca se he. 1i ht.tobe-.-renected back intothe lastic... The. lowensurfacefimoft the collar I6 is sanded or made irregular so attesermit maximum egress. of; lightiromrthe plastic tozthe surface-pi the photocell. .3. The-restoithe n e nal and. external .surfaceor. the test test is 49.1s inserted'ins de the fiashtube, and- I A raised-plastic collarv l6. i s ar rrh ow r p rt onof the tubeinzthet position indicated the. drawing, so that the. a ng h o the .testpost 2, above-it. issuflicientth a commo ate and receive; e'entirelength ,of the.- flash. t hes-h ihat st.ed.-. The. frustc conical 0.012 lar I6 is circular in cross section and slopes out polished smooth. The. lightpassingthrough a pinholein a defective 'flash tube passes into the polished sides of the test post ldown the plastic walls,'and spreads out in the conical collar, leaving'th'rough the sanded surface 56 and impinging upon the photocell surface. Due to the particular shape of the plastic body the light is thus led downwardly without substantial loss, to the tubular conical portion from where it is projected onto the photoelectric cell. The test post is preferably made of theplastic material, methyl methacrylate, commonly referred to as lucitef and plexiglas. It has been found that the best re sults are obtained when the angle 12, between the longitudinal axis of the test post and the sloping surface 54 of the conical collar is 42 degrees, and that increasing or decreasing the said angle results in a greatly diminished efliciency of light transmission to the photocell. Other materials such as clear glass may be used for the test post 2 but the light transmission efficiency thereof is much less so that not enough light is transmitted to detect the smaller holes in the flash tube covering.

While the foregoing specification sets forth the invention in specific terms, it is to be understood that numerous changes in the shape, size, arrangement and materials may be resorted to without departing from the spirit and scope of the invention claimed herein.

I claim:

1. An inspection device for discovering defective ammunition flash tubes containing holes, comprising a source of light; means for projecting said light through said holes; a photoelectric cell having a light sensitive surface; means for gathering any projected light and for directing said gathered light onto said light sensitive surface, said last mentioned means being formed of methyl methacrylate and comprising a frustoconical portion, a cylindrical extension integral and coaxial with said conical portion and extend ing from the smaller end of the frusto-conical portion, said extension being receivable in said flash tubes being tested and the larger base of said conical portion being arranged for directing said gathered light onto saidlight sensitive surface; and means actuated by said photoelectric cell responsive to said gathered directed light for ejecting from the device any flash tubes having holes.

2. In an instrument for testing the perforate or imperfor-ate condition of a hollow object having closed side walls, a base, a light-conducting tube projecting from a first side of said base, said object being adapted to extend over and about said tube, said tube having a portion flared outwardly and away from the second side of said base, alight source adjacent said tube on said first side of said base, and light-responsive means adjacent the flared end portion of said element.

3. An instrument for testing a flash tube having supposedly imperforate side Walls, a test post of light-conducting plastic having a frusto-conical exterior flange adjacent one end, the larger end of said flange being substantially planar, a photoelectric cell having its light-receiving face closely adjacent said planar end, the other end of said post being adapted to have a flash tube slid thereover, a light source positioned about said other end of said post, means shielding said flange from said light source, and means responsive to energization of said cell for removing said tube from said post.

4. An instrument for testing the perforate or imperforatecondition of a hollow object having a closed'end and side walls, .a base, a tube of light conducting material extending through said base, a sourceiof light adjacentsaid tube on a first side of said base, an element of light-conducting material fitting about said tube and having a portion fiaredoutwardly away from said tube on the second side of said base, and photoelectric cell means in contact with the flared end of said portion and responsive to any light passing from said source to said tube through perforations in the wallofsaid object while the same extends over and about said tube on said first side of said base.

5. In an instrument for testing for perforations in the walls of a generally cylindrically rigid object having one end open and one end closed, a

base, an open-ended tube of light-transmitting plastic extending through said base, said object being positioned over the first portion of said tube at a first side of said base, said tube having a circumferentially-extending frusto-conical projection on the other side of said base, a photoelectric cell in light-responsive relation with the base of said projection, a source of light adjacent said tube on the first side of said base, and means responsive to energization of said cell in response to any light passing from said source through said object to said tube, to automatically remove said object from its position over said tube.

6. In an instrument for testing for perforations, the supposedly imperforate wall of a generally cylindrical flash tube having one end closed and one end open, an opaque base having an opening therethrough, a tube of acrylic plastic extending through and fitting said opening, said tube having a frusto-conical flange extending outwardly and away from said base at one side thereof, a photo-electric cell in light-receiving contact with the larger end of said flange, a source of supply of pressure fluid, conduit means including a valve connecting said supply with the interior of said tube, a source of illumination adjacent said tube on the other side of said base, and means operated by energization of said cell in response to light passing from said source through a perforation in the wall of a flash tube to said plastic tube and thence to said cell, to open said valve and force said flash tube from its position over said plastic tube.

7. In a device for testing and sorting ammunition flash tubes having supposedly imperforate side walls and a closed end, a base having an aperture therethrough, a testing tube of acrylic plastic fitting said aperture and extending to both sides of said base, the end of said testing tube at a first side of said base being substantially coextensive with a flash tube when the latter is placed there- .over to rest on said base, said testing tube having a frusto-conical flange on the second side of said base, extending outwardly and away therefrom and having a planar end, a light-responsive cell in light-sensitive association with said planar end, a source of pressure fluid, a conduit, including a. valve, said conduit connecting said source with the interior of said testing tube, a switch, .a first circuit closing said switch in response to energization of said cell, a second circuit opening said valve in response to closing of said switch, and a source of illumination closely adjacent and extending about said testing tube ex-teriorly of a flash tube there'over.

8. The device as recited in claim 7, first and second chutes having mouths in substantial alignment with said testing tube on the first side of said base, a vane adapted to be pivoted between .a first flnfiaisfiflhdlpfiitibn $0 deflentaflash'tuhe:intora respective one of saidzchutes; .andimsnond manually operatedi switch 1 nperative; to; pivntazsaidz vane fromsaidfirstzto. saidzsecondizposition andr-simuk taneous. upen ,s aid valve independently ofzsaid firs-t switch, whereby 'said2source'nfpnessureebl'ows imperforate flash tubesint'o saidzseconds chute and perforate flash tubes 'intosaid fiwstachutei.

EEO MEISU'IER.

REEERENGES GITED;

The following references are of record in: the fil'e of thispatent:

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